SXSW’s clout as a spring launch pad is why producer Donald De Line is making his first visit a double whammy with “I Love You, Man” and Seth Rogen-starrer “Observe and Report” (Warner Bros.), helmed by Jody Hill and bowing here Monday night (movie opens April 10).

“Both films have the regular full complement of major studio marketing, but the kind of rollout you get here is impossible to get in L.A. or elsewhere,” says De Line (“Fool’s Gold,” “Body of Lies”). Comedy is thought of as disposable in some quarters and is ignored by high-profile festivals, but this festival and audience embrace comedy.”

As an executive, when De Line served as president of Touchstone Pictures and later Paramount Pictures, Toronto, Cannes and Sundance were considered the credible festival destinations. “Taking movies to SXSW is a trend that’s emerged in the last few years,” says De Line, whose current slate includes “The Jetsons,” from Austin’s own Robert Rodriguez. “You get a stamp of credibility showing here.”

With no velvet rope to separate movie folk from the event’s notoriously enthusiastic auds, SXSW delivers instant gratification for movie marketers, which is especially important in these belt-tightening times.

After the “I Love You, Man” panel at the Austin Convention Center, film co-star Jon Favreau says the festival has a unique capacity to satisfy corporate appetites through anarchy. “The idea of people Twittering back and forth is the best way to cut through expensive promotion and go directly to the audience,” he says. “This festival and its fans create a more subversive marketing groupthink.”

(If SXSW does have that talent, it comes by it honestly; Twitter largely launched here three years ago at the parallel-tracked SXSW Interactive Festival, which hosts 10,000 tech trendsetters. They were the ideal audience to intensify buzz from movie bloggers and traditional journalists with the social networking and microblogging service.)

On the indie side, the fest’s edgier fare means buyers here tend to gauge the laugh count now and follow up later — although Adam Yauch’s Oscilloscope Laboratories Monday that it acquired Argentinean Gabriel Medina’s offbeat comedy, “The Paranoids,” which premieres here tonight.

“Genre films that tap into a subculture make more sense here,” says SXSW film festival producer Janet Pierson, citing Universal’s “good luck” with its “Knocked Up” launch in 2007. It’s the reason the studio presented Sam Raimi’s “Drag Me To Hell” as a work in progress and is offering the first sneak peak of scenes from Sacha Baron Cohen’s “Bruno,” which opens July 10. “(Universal) appreciates our movie-loving audiences,” Pierson adds.